An Iranian judge must rule in a child-custody case. The husband, Nader (Peyman Maadi), devotes his energies to tending his Alzheimer’s-afflicted father (Ali-Asghar Shahbazi). His wife Simin (Leila Hatami) is the plaintiff, petitioning for divorce because she wants to take her 11-year-old daughter Termeh (Sarina Farhadi) to live abroad before their visas expire. “So the children growing up in this country don’t have a future?” the unseen judge asks. “As a mother,” Simin says,” I’d rather she didn’t grow up in these circumstances.” When the judge asks, “What circumstances?” Simin falls silent.

Western viewers of Asghar Farhadi’s A Separation may think they can guess the circumstances. The Islamic Republic of Iran is the nation run by medieval Shi’ite clerics and a daffy, dangerous politician who denies the Holocaust and may soon have a nuclear weapon to aim at Israel. It’s the country that most Republican candidates for President say they can’t wait to bomb. What responsible mother would want her child to grow up in Iran? The shock of red hair peeking from under Simin’s scarf indicates that, in her heart, she’s already left for the decadent, safer West.

But some Western moviegoers also know that, especially in the 1990s, the Islamic Republic produced (or allowed) one of the world’s most vital national cinemas. Observing the strictures of dress and custom, and often couching their social views in stories about children, directors such as Abbas Kiarostami (A Taste of Cherry), Jafar Panahi (The White Balloon) and Mohsen Makhmalbaf (Gabbeh) and his daughter Samira (Blackboards) wove a rich movie fabric indebted to both Italian neo-realism and Latin American magical realism. In the past decade, the clerics clamped down. Kiarostami made his last film, Certified Copy, in Italy with Juliette Binoche as his star. The voices of the outspoken Mahkmalbafs have been muted. And Panahi, a supporter of Iran’s Green Revolution, was sentenced to six years in jail for making “propaganda against the regime.”

In this charged atmosphere, a state-approved director like Farhadi can seem the 21st-century equivalent of a fascist collaborator. A Separation, which the New York and Toronto critics’ groups and the National Board of Review have chosen as the year’s best foreign film, is indeed Iran’s official selection for the Foreign-Language Film Academy Award. But it is not official art: stridently clerical, or winsome and neutered. Farhadi’s fascinating and seductive drama reveals (exposes, if you like) modern Iranians as soldiers in an implicit war on many fronts: secular vs. religious, urban vs. rural, middle-class vs. working-class. In this battle, the collateral damage may be the children, and sometimes the truth.

Simin’s and Nader’s divorce debate is the first of many complex issues raised and passionately argued in A Separation. In that opening scene, filmed as one four-minute shot, Simin and Nader argue their case directly to the camera, as if the director is instructing the moviegoer to be the judge in a matter of Solomonic import and delicacy — and in that rare film that escapes the usually trim narrative confines of the screen and lodges and lives in the minds of viewers. For days after seeing the movie, you may continue to mull and debate its dilemmas.

“I think it’s insulting to an audience to make them sit and watch a film,” Farhadi has said, “and then give them a message in one sentence.” A Separation raises a host of questions — about family, class, religion and, implicitly, politics — and lets the viewer decide. The film is no art-house conundrum, teasing viewers by withholding information, but an acknowledgment that, in life more than films, people have profound if not always valid reasons for their behavior. In the urgent clash of actions and personalities, almost everyone can be mostly right and crucially, culpably wrong.

Simin moves out of the house and in with her folks; daughter Termeh stays with dad and his ailing dad, perhaps believing that, if she does, Mom will stay close by. But Grandpa, in his depleted state, doesn’t know much except that he needs and loves his daughter-in-law; in one brief scene he clutches her wrist and won’t let go. Simin’s absence will require a caretaker for Grandpa while Nader is at work and Termeh at school. The parents hire Razieh (Sareh Bayat), a devout working-class woman who brings her five-year old Somayeh (Kimia Hosseini) along for mommy-daughter workdays. The commute takes hours, but Razieh needs the money to support her husband Hojjat (Shahab Hosseini), a carpenter who lost his job and has been in debtor’s prison.

Got all that? Good, because now things get knotty. One life is imperiled, another lost, in actions stemming from the characters’ completely understandable, even noble motives. Have you experienced events that turn your stomach with the sudden realization that, from this moment, your life will be different and worse? Domestic cataclysms of that sort strike Nader and Razieh, staining them and their spouses and landing both families in court. A master twister of plots and personalities (his film won the Los Angeles Film Critics’ screenplay award, a prize well earned), Farhadi eventually reveals sad and surprising secrets without wrapping up a message in one sentence.

Some critics reviewing David Fincher’s The Girl With the Dragon Tattoo wondered aloud why a novel that has already been a hit Swedish film needed to be redone by Hollywood. A Separation, though, is ready-made for an American remake. It’s basically a police procedural and a legal drama — Law & Order: Tehran — where the judge has to rule if a crime was committed and the civilians have to solve the mystery. It’s People’s Court, Divorce Court and, because everyone argues at once and Hojjat is a bit of a hothead, an Iranian Jerry Springer. The bourgie, skeptical Nader and the rougher, Quran-spouting Hojjat could easily be transposed into American roles: the urban liberal and the rural fundamentalist. In court, when his testimony is challenged, Nader says, “I should swear to God?” “Like you believe in God,” Hojjat replies contemptuously. “No,,” Nader spits out, “God is for your type only.”

A Separation also has so many plot points in common with the new Roman Polanski film Carnage that the two movies might have been made by bright students given the same assignment at a screenwriting seminar. Both stories are about two married couples from different social classes who fall into a catastrophic argument involving their respective children. In Farhadi’s infinitely superior film, the children — the studious, watchful Termeh (played by the director’s daughter) and the elfin, compulsively truth-telling Somayeh (played by the daughter of the man who plays her father) — are important participants. Through their innocent but knowing eyes we can calibrate the righteous claims and factual evasions of the adults.

One other peculiar affinity: A Separation could be a cousin of films from the new Israeli cinema, which feature the same culture clashes, the same big-city contemporary setting, the same love of argument and judicious, almost Talmudic weighing of opposing motives. (To cement the connection, Farhadi tosses a traditional Jewish mother into the mix: Simin’s nattering mom, who, when the estranged Nader drops by, says, “Not divorced yet, and already ignoring us!”)

And like so many Israeli films (The Band’s Visit, Nina’s Tragedies, Footnotes), A Separation boasts superb ensemble acting, most notably from the female leads: the red-headed, Ingrid Bergman-looking Hatami, who studied French literature in Switzerland and could be a luminary in European movies; and, in her film debut, Bayat, whose large eyes and volcanic sanctity suggest an Iranian Anna Magnani. Every cramped or conflicted emotion plays luminously across Bayat’s face—a soul crying for God’s liberating help.

Actually, however ripe A Separation might seem for being adapted into a smart American film, Hollywood shouldn’t bother. Farhadi’s movie is just about perfect as it is.